In defense of the volcanoes

We have already defended the role that greenhouse gases play in the Earth's climate and in the development of life.

Today we are dealing with other essential astrobiological agents: volcanoes.

Their beauty and their role in the creation and maintenance of our atmosphere and climatic conditions make volcanoes not only passionate and occupy geologists but also astronomers, being essential to understand the evolution and habitability of the planets.

From the impressive pictures of Fujiyama, Mount Teide, Kilimanjaro or Cotopaxi, to the stories about Vesuvius and the destruction of Pompeii, passing through the beauty of the telescopes at the top of Mauna Kea, the rivers of lava flowing from the Kilauea or the columns of smoke over Etna or Popocatepetl, the volcanoes surround us and fascinate us.

Perhaps they have affected our subconscious in such a way that the importance of volcanoes for the Earth is manifested in our fascination with these giants, who when they awaken they wreak havoc and death, even though life as we know it would not be possible without them.

If an extraterrestrial civilization also fascinated by volcanoes came to Earth it would hardly find a few assets.

Compared to the past, today our planet is quite calm, although there are thousands of volcanoes that can potentially erupt.

Many more active volcanoes can be found on Jupiter's moon Io, which has more than 100 volcanoes spewing lava and gases at once.

Among them, the Pele (named in honor of the goddess of volcanoes in Hawaii, and similar in name to a Martinique volcano) has persistent activity that was first detected by Voyager 1 in 1979, and later by probes. Galileo, Cassini and New Horizons between 1996 and 2007. Although the most spectacular thing that

sent us

from Io was the 330 km high plume of the Tvashtar volcano (named in honor of the god of blacksmiths for the Hindus).

That height is 15% of the radius of Io, it would be as if a volcano on Earth was launching material up to 1000 km high, higher than the orbit of the Iridium satellites.

Impressive volcanoes can also be found on Mars, where Mount Olympus is located, which is typically named as the highest volcano in the Solar System at 21 kilometers high (although there is a higher mountain on the asteroid Vesta) and an area comparable to France, or the Dawn, one of the largest in the Solar System, more than double that of Olympus.

Perhaps what we should most recognize about volcanoes is that thanks to them we have an atmosphere

If the extraterrestrial volcanoes releasing gases and molten rock are impressive, those that we know that release steam and lava are not far behind, but not rock but water, ammonia or liquid methane, in the style of our geysers but more powerful and with the capacity to form volcanic cones and mountains.

Some examples of these so-called cryovolcanoes can be found on Saturn's moon Enceladus, which throws water at thousands of kilometers per hour, more than the escape velocity of the satellite, so it is lost in space.

We have also discovered dormant cryovolcanoes on the dwarf planet Ceres, on Saturn's satellite Titan or the Jovian moon Europa, which indicates the presence of liquid water and / or methane, including oceans, under the icy surface of those moons that could carry associated the presence of some kind of life.

The beauty of volcanoes, terrestrial and extraterrestrial, is not the only aspect that makes them special.

Perhaps what we should most recognize about volcanoes is that thanks to them we have an atmosphere.

The planetary formation models establish that when the solid part of the rocky terrestrial planets (Mercury, Venus, Earth and Mars) was created, they were very hot and the gas molecules they could have were moving too fast, more than the speed escape, so the atmosphere we call primary must have been lost early in the history of our planet.

This was not the case on the colder and more massive planets, Jupiter, Saturn, Uranus and Neptune, which still retain that primary atmosphere today.

Returning to Earth, it was the volcanoes that, as the planet cooled, released gases to the outside, giving rise to the secondary atmosphere that we see today (or we could even speak of a tertiary one today).

Another great achievement of volcanoes and a gift for our lives has to do with their relationship with greenhouse gases and the internal heat they release.

Several studies have seen a direct, although not simple, relationship between the end of some ice ages on Earth and volcanic activity.

The most natural thing would be to think that the heat from volcanoes can melt the ice and cause or at least help end an ice age, but the reality seems more complicated.

In the last ice age, the beginning of the liquefaction of the ice blocks, which had caused a great erosion of the earth's crust, could cause an increase in volcanic activity.

Again, innocently, one might think that this increase could accelerate global warming, but the greenhouse gases and ash released by volcanoes can increase the temperature of the planet by increasing the greenhouse effect or they can have the opposite effect, cool the planet.

In fact, in the 13th to 15th centuries, a series of volcanic eruptions seems to have caused colder winters for decades, the so-called Little Ice Age, which affected agriculture in certain areas of the northern hemisphere and could even favor advances in navigation. and promote the expansion of the European empires of the Modern Age.

There are also studies that indicate an action of volcanoes in the ocean currents of the Jurassic that led to an ice age.

In conclusion, volcanoes are another key player in Earth's delicate climatic and vital balance, which humanity has joined in recent decades.

The role of volcanoes and cryovolcanoes in the existence of life, as well as their usefulness to understand the interior of the planets, which gives information about their formation, is unquestionable, they deserve to break a spear for them.

The discovery of volcanoes on extrasolar planet, perhaps through the detection of sulfur dioxide gases during the period of time that the volcano was active or even in visible plumes during the transit of the planet in front of its star, is a goal of astrobiologists for the coming years and decades.

Pablo G. Pérez González

Patricia Sánchez Blázquez

Cosmic Void

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